共查询到20条相似文献，搜索用时 15 毫秒
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Junghoon Lee Sangwoo Shin Youhua Jiang Chanyoung Jeong Howard A. Stone Chang‐Hwan Choi 《Advanced functional materials》2017,27(15)
The major drawback of current passivation techniques for preventing corrosion is the lack of ability to withstand any external damages or local defects. In this study, oil‐impregnated nanoporous anodic aluminum oxide (AAO) layers are investigated to overcome such limitations and thus advance corrosion protection. By completely filling hydrophobized nanopores with oil via a solvent exchange method, a highly water‐repellent surface that prevents the penetration of corrosive media into the AAO layer and hence the corrosion of aluminum is achieved. The impregnation of oil into the hydrophobic nanoporous AAO layer enhances the corrosion resistance of an AAO layer by two and four orders of magnitude compared to that of a hydrophobic (i.e., air‐entrained) and a bare (hydrophilic) AAO, respectively. In the presence of local defects, the oil impregnated within the hydrophobic nanoporous AAO layer naturally permeates into the defects and ultimately inhibits the exposure of the aluminum surface to corrosive media. Whereas the corrosion current density of the air‐entrained hydrophobic AAO layer increases by more than 30 times after cracks, that of the oil‐impregnated AAO layer increases by no more than 4 times, showing superior anticorrosion property even after there are cracks, owing to the effective self‐healing capability. 相似文献
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Benjamin J. Blaiszik Marta Baginska Scott R. White Nancy R. Sottos 《Advanced functional materials》2010,20(20):3547-3554
Autonomic self‐healing of interfacial damage in a model single‐fiber composite is achieved through sequestration of ca. 1.5 μm diameter dicyclopentadiene (DCPD) healing‐agent‐filled capsules and recrystallized Grubbs’ catalyst to the fiber/matrix interface. When damage initiates at the fiber/matrix interface, the capsules on the fiber surface rupture, and healing agent is released into the crack plane where it contacts the catalyst, initiating polymerization. A protocol for characterizing the efficiency of interfacial healing for the single‐fiber system is established. Interfacial shear strength (IFSS), a measure of the bond strength between the fiber and matrix, is evaluated for microbond specimens consisting of a single self‐healing functionalized fiber embedded in a microdroplet of epoxy. The initial (virgin) IFSS is equivalent or enhanced by the addition of capsules and catalyst to the interface and up to 44% average recovery of IFSS is achieved in self‐healing samples after full interfacial debonding. Examination of the fracture interfaces by scanning electron microscopy reveals further evidence of a polyDCPD film in self‐healing samples. Recovery of IFSS is dictated by the bond strength of polyDCPD to the surrounding epoxy matrix. 相似文献
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Benjamin J. Blaiszik Marta Baginska Scott R. White Nancy R. Sottos 《Advanced functional materials》2010,20(20):3401-3401
Autonomic self‐healing of interfacial damage in a model single‐fiber composite is achieved through sequestration of ca. 1.5 μm diameter dicyclopentadiene (DCPD) healing‐agent‐filled capsules and recrystallized Grubbs’ catalyst to the fiber/matrix interface. When damage initiates at the fiber/matrix interface, the capsules on the fiber surface rupture, and healing agent is released into the crack plane where it contacts the catalyst, initiating polymerization. A protocol for characterizing the efficiency of interfacial healing for the single‐fiber system is established. Interfacial shear strength (IFSS), a measure of the bond strength between the fiber and matrix, is evaluated for microbond specimens consisting of a single self‐healing functionalized fiber embedded in a microdroplet of epoxy. The initial (virgin) IFSS is equivalent or enhanced by the addition of capsules and catalyst to the interface and up to 44% average recovery of IFSS is achieved in self‐healing samples after full interfacial debonding. Examination of the fracture interfaces by scanning electron microscopy reveals further evidence of a polyDCPD film in self‐healing samples. Recovery of IFSS is dictated by the bond strength of polyDCPD to the surrounding epoxy matrix. 相似文献
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Tim S. Coope Ulrich F. J. Mayer Duncan F. Wass Richard S. Trask Ian P. Bond 《Advanced functional materials》2011,21(24):4624-4631
A novel Lewis acid‐catalysed self‐healing system is investigated for implementation into epoxy‐based fibre reinforced polymer (FRP) composite materials. The catalyst, scandium(III) triflate, is selected using a qualitative approach and subsequently embedded with pre‐synthesised epoxy‐solvent loaded microcapsules, into an epoxy resin. Healing is initiated when microcapsules are ruptured at the onset of crack propagation. The epoxy monomer healing agent contained within actively undergoes ring‐opening polymerisation (ROP) on contact with the locally dispersed catalyst, forming a new polymer to bridge the two fractured crack planes. Self‐healing performance is quantified using a tapered double cantilever beam (TDCB) test specimen and the effects of microcapsule content and healing temperature and time are all independently considered. As an initial ‘proof of concept’ study, results show that a material recovery value of greater than 80% fracture strength is achieved for this novel Lewis acid‐catalysed self‐healing epoxy resin. 相似文献
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Svetlana V. Lamaka Dmitry G. Shchukin Daria V. Andreeva Mikhail L. Zheludkevich Helmuth Möhwald Mario G. S. Ferreira 《Advanced functional materials》2008,18(20):3137-3147
This work presents a new type of feed‐back active coating with inhibitor‐containing reservoirs for corrosion protection of metallic substrates. The reservoirs are composed of stratified layers of oppositely charged polyelectrolytes deposited on AA2024 aluminum alloy coated with hybrid sol‐gel film. The layer‐by‐layer assembled polyelectrolyte film with the entrapped corrosion inhibitor is constructed by sequential spray‐coating deposition of water solutions of poly(ethyleneimine), poly(sodium styrenesulfonate) and 8‐hydroxyquiniline on the top of the sol‐gel coating. The active corrosion protection of AA2024 alloy coated with SiO2/ZrO2 sol‐gel film and modified by polyelectrolytes is demonstrated by electrochemical impedance spectroscopy and scanning vibrating electrode technique. The results obtained here show that polyelectrolyte films deposited atop of the hybrid sol‐gel coating on AA2024 alloy remarkably improve the long‐term protection performance providing additional “intelligent” anticorrosion effect that results from delivery of inhibiting species “on demand”. This becomes possible since the configuration of the polyelectrolyte molecules depends on the presence of H+ ions making the polyelectrolyte film sensitive to the pH of the surrounding solution. The source of local pH changes is the corrosion process starting in the micro‐ and nano‐defects leading to increased permeability of the polyelectrolyte reservoir and, consequently, to controllable release of entrapped inhibitor. 相似文献
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Ekaterina V. Skorb Dmitri Fix Daria V. Andreeva Helmuth Möhwald Dmitry G. Shchukin 《Advanced functional materials》2009,19(15):2373-2379
The development of active corrosion protection systems for metallic substrates is an issue of prime importance for many industrial applications. The present work shows a new contribution to the design of a new protective system based on surface modified mesoporous silica containers. Incorporation of silica‐based containers into special sol–gel matrix allows for a self‐healing effect to be achieved during the corrosion process. The self‐healing ability occurs due to release of entrapped corrosion inhibitors in response to pH changes caused by the corrosion process. A silica–zirconia‐based hybrid film is used in this work as a coating matrix deposited on AA2024 aluminum alloy. Mesoporous silica nano‐particles are covered layer‐by‐layer with polyelectrolyte layers and loaded with inhibitor [2‐(benzothiazol‐2‐ylsulfanyl)‐succinic acid]. The hybrid film with nanocontainers reveals enhanced long‐term corrosion protection in comparison with the individual sol–gel films. The scanning vibrating electrode technique also shows an effective healing ability of containers to cure the corrosion defects. This effect is due to the release of the corrosion inhibitor triggered by the corrosion processes started in the cavities. The approach described herein can be used in many applications where active corrosion protection of materials is required. 相似文献
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Dimitriya Borisova Dilek Akçakayıran Matthias Schenderlein Helmuth Möhwald Dmitry G. Shchukin 《Advanced functional materials》2013,23(30):3799-3812
Organic coatings based on inhibitor loaded inorganic containers for smart corrosion inhibition are presented. The overall coating performance is strongly influenced by the containers as well as their inhibitor capacity, compatibility with the coating matrix, and size. The important effect of container size is described for the first time in this work by investigating two types of mesoporous silica containers of different diameters: 80 and 700 nm. The coating physical properties (thickness and adhesion) are comparable for both container types. In contrast, the coating barrier properties are strongly influenced by the container size as assessed with electrochemical impedance spectroscopy (EIS). The incorporation of bigger containers reduces the coating resistance by a factor of two. Surprisingly, despite the similar amounts (20 wt%) of loaded inhibitor (2‐mercaptobenzothiazole), different active inhibition ability is detected with the scanning vibrating electrode technique (SVET). Therefore, it is found that coatings with smaller containers exhibit better self‐healing performance. 相似文献
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Natascha Kuhl Stefan Bode Ranjita K. Bose Jürgen Vitz Andreas Seifert Stephanie Hoeppener Santiago J. Garcia Stefan Spange Sybrand van der Zwaag Martin D. Hager Ulrich S. Schubert 《Advanced functional materials》2015,25(22):3295-3301
The utilization of dynamic covalent and noncovalent bonds in polymeric materials offers the possibility to regenerate mechanical damage, inflicted on the material, and is therefore of great interest in the field of self‐healing materials. For the design of a new class of self‐healing materials, methacrylate containing copolymers with acylhydrazones as reversible covalent crosslinkers are utilized. The self‐healing polymer networks are obtained by a bulk polymerization of an acylhydrazone crosslinker and commercially available methacrylates as comonomers to fine‐tune the Tg of the systems. The influence of the amount of acylhydrazone crosslinker and the self‐healing behavior of the polymers is studied in detail. Furthermore, the basic healing mechanism and the corresponding mechanical properties are analyzed. 相似文献
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Self‐healing antifouling materials have gained rapidly increasing interest over the past decade and have been studied and used in a rapidly increasing range of applications. Recent developments and challenges in self‐healing antifouling materials are summarized in four sections: first, the different mechanisms for both antifouling and self‐healing are briefly discussed. Second, three main categories of self‐healing antifouling materials based on surface replenishing and dynamic covalent and noncovalent interactions are discussed, with a focus on the preparation, characterization, and central characteristics of different self‐healing antifouling materials. Third, different types of potential applications of self‐healing antifouling materials are summarized, such as injectable hydrogels and oil/water separations. Finally, a summary of future development of the field is provided, and a number of critical limitations that are still outstanding are highlighted. 相似文献
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A. C. C. Esteves Y. Luo M. W. P. van de Put C. C. M. Carcouët G. de With 《Advanced functional materials》2014,24(7):986-992
Robust dual structured superhydrophobic coatings which replenish spontaneously their surface chemical composition on new multi‐scale structured surfaces, recreated upon damage, are described. The surface repair occurs at room temperature, via intrinsic elements of the coatings, all covalently bonded. These coatings can be prepared from all‐in‐one dispersions by a simple drop‐cast method, with different thicknesses and on various substrates. The critical factors to optimize the self‐replenishment are described and three main design principles are postulated. The superhydrofobicity of the coatings is maintained even after 500 abrasion cycles. The principles reported can be extended towards self‐healing other surface‐dependent functionalities, that is, anti‐bacteria, anti‐fouling, or drag‐reduction, which will maintain high performance levels all through their life‐cycle with low cost and energy demand for maintenance and surface repair. 相似文献
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Liyang Shi Fanlu Wang Wei Zhu Zongpu Xu Sabine Fuchs Jöns Hilborn Liangjun Zhu Qi Ma Yingjie Wang Xisheng Weng Dmitri A. Ossipov 《Advanced functional materials》2017,27(37)
Despite advances in the development of silk fibroin (SF)‐based hydrogels, current methods for SF gelation show significant limitations such as lack of reversible crosslinking, use of nonphysiological conditions, and difficulties in controlling gelation time. In the present study, a strategy based on dynamic metal‐ligand coordination chemistry is developed to assemble SF‐based hydrogel under physiological conditions between SF microfibers (mSF) and a polysaccharide binder. The presented SF‐based hydrogel exhibits shear‐thinning and autonomous self‐healing properties, thereby enabling the filling of irregularly shaped tissue defects without gel fragmentation. A biomineralization approach is used to generate calcium phosphate‐coated mSF, which is chelated by bisphosphonate ligands of the binder to form reversible crosslinkages. Robust dually crosslinked (DC) hydrogel is obtained through photopolymerization of acrylamide groups of the binder. DC SF‐based hydrogel supports stem cell proliferation in vitro and accelerates bone regeneration in cranial critical size defects without any additional morphogenes delivered. The developed self‐healing and photopolymerizable SF‐based hydrogel possesses significant potential for bone regeneration application with the advantages of injectability and fit‐to‐shape molding. 相似文献
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Guopu Chen Yunru Yu Xiuwen Wu Gefei Wang Jianan Ren Yuanjin Zhao 《Advanced functional materials》2018,28(33)
Inspired by the coordinated multiple healing mechanism of the organism, a four‐armed benzaldehyde‐terminated polyethylene glycol and dodecyl‐modified chitosan hybrid hydrogel with vascular endothelial growth factor (VEGF) encapsulation are presented for efficient and versatile wound healing. The hybrid hydrogel is formed through the reversible Schiff base and possesses self‐healing capability. As the dodecyl tails can insert themselves into and be anchored onto the lipid bilayer of the cell membrane, the hybrid hydrogel has outstanding tissue adhesion, blood cell coagulation and hemostasis, anti‐infection, and cell recruitment functions. Moreover, by loading in and controllably releasing VEGF from the hybrid hydrogel, the processes of cell proliferation and tissue remodeling in the wound bed can be significantly improved. Based on an in vivo study of the multifunctional hybrid hydrogel, it is demonstrated that acute tissue injuries such as vessel bleeding and liver bleeding can be repaired immediately because of the outstanding adhesion and hemostasis features of the hydrogel. Moreover, the chronic wound‐healing process of an infectious full‐thickness skin defect model can also be significantly enhanced by promoting angiogenesis, collagen deposition, macrophage polarization, and granulation tissue formation. Thus, this multifunctional hybrid hydrogel is potentially valuable for clinical applications. 相似文献
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Christopher J. Hansen Scott R. White Nancy R. Sottos Jennifer A. Lewis 《Advanced functional materials》2011,21(22):4320-4326
Self‐healing materials with dual interpenetrating microvascular networks enable two‐part healing chemistries and repeated healing of damage in a localized region. 1 However, due to slow healing kinetics, multiple days are required between damage events to recover mechanical performance under ambient conditions. By directly writing a third interdigitated microvascular network within these epoxy coating/substrate architectures to enable in situ thermal regulation, the characteristic healing time is reduced by an order of magnitude. Specifically, this third network provides a conduit for circulating a temperature‐controlled fluid that rapidly heats the locally damaged region leading to a sharp reduction in the time required for mechanical property restoration. 相似文献
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Seyoung Kee Md Azimul Haque Daniel Corzo Husam N. Alshareef Derya Baran 《Advanced functional materials》2019,29(51)
With the advent of flexible and wearable electronics and sensors, there is an urgent need to develop energy‐harvesting solutions that are compatible with such wearables. However, many of the proposed energy‐harvesting solutions lack the necessary mechanical properties, which make them susceptible to damage by repetitive and continuous mechanical stresses, leading to serious degradation in device performance. Developing new energy materials that possess high deformability and self‐healability is essential to realize self‐powered devices. Herein, a thermoelectric ternary composite is demonstrated that possesses both self‐healing and stretchable properties produced via 3D‐printing method. The ternary composite films provide stable thermoelectric performance during viscoelastic deformation, up to 35% tensile strain. Importantly, after being completely severed by cutting, the composite films autonomously recover their thermoelectric properties with a rapid response time of around one second. Using this self‐healable and solution‐processable composite, 3D‐printed thermoelectric generators are fabricated, which retain above 85% of their initial power output, even after repetitive cutting and self‐healing. This approach represents a significant step in achieving damage‐free and truly wearable 3D‐printed organic thermoelectrics. 相似文献
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Qiang Chen Lin Zhu Hong Chen Hongli Yan Lina Huang Jia Yang Jie Zheng 《Advanced functional materials》2015,25(10):1598-1607
Double network (DN) hydrogels with two strong asymmetric networks being chemically linked have demonstrated their excellent mechanical properties as the toughest hydrogels, but chemically linked DN gels often exhibit negligible fatigue resistance and poor self‐healing property due to the irreversible chain breaks in covalent‐linked networks. Here, a new design strategy is proposed and demonstrated to improve both fatigue resistance and self‐healing property of DN gels by introducing a ductile, nonsoft gel with strong hydrophobic interactions as the second network. Based on this design strategy, a new type of fully physically cross‐linked Agar/hydrophobically associated polyacrylamide (HPAAm) DN gels are synthesized by a simple one‐pot method. Agar/HPAAm DN gels exhibit excellent mechanical strength and high toughness, comparable to the reported DN gels. More importantly, because the ductile and tough second network of HPAAm can bear stress and reconstruct network structure, Agar/HPAAm DN gels also demonstrate rapid self‐recovery, remarkable fatigue resistance, and notable self‐healing property without any external stimuli at room temperature. In contrast to the former DN gels in both network structures and underlying association forces, this new design strategy to prepare highly mechanical DN gels provides a new avenue to better understand the fundamental structure‐property relationship of DN hydrogels, thus broadening current hydrogel research and applications. 相似文献
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